1. Field of the Invention
The present invention relates preparing tubular meat products and more particularly to a tubular elasticated net with an inextensible weft.
2. Description of the Prior Art
Tubular elasticated netting is used to encapsulate meat products such as joints of beef or pork. The net remains on the joint during cooking to retain the shape and integrity of the joint. An example of a knitting machine which produces such netting is to be found in our British Patent No. 2333301. An example of a machine which packages meat in such netting is to be found in our British Patent No. 2380179. Reference is made to the specifications of these Patents for a clearer understanding of the present invention.
In addition to its use on joints of meat elasticated netting is also used in the preparation and presentation of cooked meat products such as sausages, hams, salamis and frankfurters. Portions of these products are encased in plastics, or sometimes fibrous, enclosures which limit their expansion during cooking and result in the uniform, cylindrical cooked meat products which supermarkets require for presentation and sales purposes, and which facilitate slicing. Emulsions are commonly contained in collagen film. However it is necessary for the meat to be squeezed during cooking to prevent distortions due to the formation of voids as fats are melted. To achieve this, the imperforate casing has been enclosed in a tubular, elasticated net. However, unless the stretch of the elastic is limited, the result is unlikely to be the desired, uniform cylinder.
U.S. Pat. No. 1,679,822 discloses a rubber thread covered with helically wound textile threads. The latter are said to limit the stretch of the rubber as they straighten, i.e. as the pitch of the spiral windings increases. European Patent No. 1154696 discloses the use of such a covered thread as the weft of a net used to encapsulate food products. The yarn windings on the rubber thread limit the stretch of the rubber.
Nets of the kind described in European Patent No. 1154696 have been in extensive commercial use throughout the world for at least the past twenty years. Problems arising from the use of such nets to control the shape of cooked meat products include the following: As acknowledged in U.S. Pat. No. 1,679,822, if inextensible and rubber threads are simply laid side-by-side and covered by yarn windings, the resulting thread is so deformed as to be unmanageable and unsightly except when under extreme tension. If a fine cotton or nylon thread is wound helically around the rubber thread, it is easily broken when tensioned. The use of a thicker, stronger inextensible thread is not only expensive but greatly diminishes the stretchability of the rubber. In any event the limit of stretch of such an assembly is not precisely determinable. The extent to which the yarn will bite into the rubber as the latter is stretched will vary as will the ultimate pitch angle of the helically wound yarn.